1. Field of the Invention
The present invention relates to electric dry shavers of the type having a pair of movable cutters driven by an oscillating drive arm in shearing relationship with a fixed cutter in the form of a thin metallic foil comb, the movable cutters being biased into shearing engagement with the inner surface of the comb. The invention relates in particular to means for supporting, driving and power cleaning the movable cutters.
2. Description of the Prior Art
In electric dry shavers it is typical to provide one or more elongated cutter blocks, each carrying a plurality of part-circular cutter blades, which are resiliently biased toward shearing engagement with the inner surface of a fixed cutter in the form of a perforated comb formed of a thin metallic foil. The cutter blocks are reciprocatively driven in shearing relationship with the comb by an oscillating electric motor-driven drive arm.
Various means are provided for coupling the drive arm to the cutter blocks. A common technique is to mount the cutter blocks on one or more rigid drive blocks, which are, in turn, coupled to the drive arm. This provides an accurate transmission of the driving motion of the drive arm to the cutter blocks, but it does not permit any variation in the positions and movement of the cutter blocks. This can be troublesome, since it is not uncommon for there to be small shape or position discrepancies, or for there to be slight deflections of the comb in response to engagement with the face of the user in operation. Such discrepancies reduce the shaving efficiency and deformations or deflections can cause interference between the comb and the moving cutter blocks, resulting in poor cutting, or even damage to the comb.
At least one prior shaver has addressed this problem by providing a type of universal mounting for the cutter blocks which permits slight pivotal movements of the cutter blocks about mutually perpendicular pivot axes, so that the cutter blocks can automatically adjust their positions to follow the shape of the comb in use. However, this prior arrangement is a complicated multi-part construction utilizing multiple swivel joints.
It is also known to provide a dual-head shaver with mounting of the comb heads on a pair of unitary molded support frames having resiliently hinged portions which accommodate relative movement of the heads in use. But in this shaver, disclosed, e.g., in U.S. Pat. No. 4,797,997, the movable cutters are supported by a complicated, multi-part construction which has only vertical flexibility.